RGO Racing Gear Oil (85W-140)

I installed 4.10's in my Mustang GT and had some noise due to how they cut the gears now. Changed the fluids many times, rechecked wear patter's...bla...bla it was all SAT but had constant gear noise 40 MPH+ Long story short looked around and decided to use this stuff with 2-4oz bottles of Ford Friction modifier fixed my problems! It's so much more quiet now, it feels smoother and the differential is actually a little cooler when I check it after driving. Get this stuff after you do a rebuild and break in your gears and it's time to changed the oil and you are going to be very happy! Yes, a little more expensive then most brands (other than Amsoil which is close to this GL-6 stuff) you pay a premium penny but you won't ever have to worry about it again. Hands down worth it!

2005 GTO I recently purchased with 108k miles had a TON of clunking noise and grinding in the rear. I bought 2 bottles of Torco 85-140 (holds 1.6) and stopped by a local FORD dealership to buy a 4oz bottle of their friction modifier($8). Mixed the entire 4oz of modifier into the 1st bottle of Torco, drained the rear end gear oil (simple) and added that bottle with the modifier and another 2/3 of the 2nd bottle. Unbelievable how INSTANTLY this stopped ever noise in the rear end I've had since I bought the car. This stuff is a dream come true & I'll never put another fluid in my GTO's rear gear.

Best Fluid For 2006 GTO Differential

The best gear oil for the GTO rear but make sure to get posi additive too.

So far this stuff has a noticable difference while driving. The rear end doesn't feel so sluggish and very affordable as well.

Torco gear oil, non synthetic. I changed the rear gears and this was the reommended break in and full time service lube.

I recently purchased a 2004 GTO. I cleaned it all up put all new parts and made her look real nice. When I put brand new tires on, after a long ride I would notice an awful noise from the rear end. It sounded like a loud clicking like a clutch slip noise,. It was very unnerving and I thought I was going to have to spend $1000 on a new rear end. I was recommended by a fellow GTO owner that I change my rear DIff fluid and use the Torco racing gear lube in conjunction with their type F friction modifier. I did this, and it was like magic. I can drive the car any distance without any noise from the rear end at all. If you need to change your rear Diff fluid in your high-performance vehicle with a limited slip differential? This stuff is highly recommended! Don’t waste your money on any other product. This stuff saved me $1000 on a new rear end. I got 2 quarts and the friction modifier on Amazon for just over $60 with tax. Excellent product! Customer for LIFE!

Works great in my '06 GTO, just be sure to get the Type F friction modifier and not the GM one as the Brog Warner/Dana/Spicer M80 diff is a whole different beast. If you have a GTO with a moderate amount of clunking, I'd say go for it. It decreased the occurrence of clunking sounds for me and I know a few other GTO guys who've had results with it as well. Worst case is it doesn't help and now you're running higher quality fluids in the diff.